Prior art modular conveyor chains include rows of chain modules, each module having a plurality of spaced link ends which intermesh with the complementary link ends projecting from a module in an adjacent row. A pivot pin runs through the interengaged or meshing link ends to permit pivotal movement of the modules with respect to each other. Typically the pivot pin projects from each edge or side of the conveyor chain and is provided with a head which prevents the pin from moving transversely of the conveyor. The head on one end of the hinge pin can be preformed, but in most cases the heads are formed by heat and pressure after the pin has been placed in position. The heads project from the sides of the conveyor chain and can catch or drag on adjacent structures and require additional lateral clearance between the conveyor and the conveyor guide or between adjacent conveyor chains.
The prior art conveyors generally have modules of similar width engaging one another. This can result in forces being set up tending to separate laterally adjacent modules.
Examples of prior art chains are illustrated in Lapeyre, et al. U.S. Pat. No. 3,870,141, issued Mar. 11, 1975; the Lapeyre U.S. Pat. No. 4,051,949, issued Oct. 4, 1977; the Lapeyre U.S. Pat. No. Re. 30,341, issued July 22, 1980; and the Kewley, et al. U.S. Pat. No. 4,159,763, issued July 3, 1979.